A powered toothbrush is designed to assist a user by mechanically moving the head of the toothbrush. One approach is to provide a vibratory element in the body of the toothbrush. U.S. Published Application No. 2002/0124333 relates to a mechanical vibratory device which causes the head part to vibrate. The vibratory device is accommodated in a front head part of the toothbrush, or in a neck-part region adjacent to the head part, said neck part connecting the head part to the handle, and is operatively connected to a power source, accommodated in the handle, via electrical connections running in the neck part, a vibration-dampening element preferably being provided in order to prevent vibration transmission to the handle, this achieves the situation where the vibrations which effect the improved cleaning action are produced predominantly in the head part and can only be felt to a slight extent in the handle, as a result of which comfortable handling of the toothbrush is achieved.
A number of approaches have been taken to provide flexibility to the bristles during use of a toothbrush. U.S. Pat. No. 5,970,564, for example, relates to a toothbrush having an elastomeric ridge wherein there is a center array of bristles and there is a side array of bristles mounted in elastomeric boots. A number of patents relate to a toothbrush head having sets of bristles, each of which is mounted to a non-rigid or elastic support element. Examples of these approaches are found in U.S. Pat. Nos. 1,770,195, 2,244,098, 6,161,245 and 6,311,360 and in French Patent No. 38440.
The head of a conventional toothbrush typically has a flat or slightly altered surface to which cleaning elements are attached. Usually the cleaning elements are strands of plastic material(s) formed into tufts, bundles or other groupings. A goal of many toothbrushes is to accommodate the cleaning element profile to that of the teeth being cleaned. Achieving that goal is complicated by the difficulty in matching a toothbrush profile to the complex surface of a typical set of human teeth. The latter generally lie in a “C” shaped curve which presents the need for a brush to address a convex outer curve and a concave inner curve. In addition, the toothbrush should be capable of cleaning irregularities on the tooth surface as well as the interproximal area between teeth.
It is well known that the ideal brushing technique from a dental hygiene perspective is an up and down stroke along the vertical surface of teeth which massages the gums while cleaning the teeth. However, due to a number of factors, including ergonomic difficulties, haste, lack of education or the like, few consumers use the recommended brushing technique. Rather, the typical consumer brushes across their teeth in a horizontal motion rather than a vertical movement. Various approaches have been taken by others to translate horizontal brush movement into partial vertical movement of the bristles or cleaning elements.
U.S. Pat. No. 4,783,869 relates to translation of horizontal to vertical movement of cleaning elements through use of a helix groove in a movable shaft within a toothbrush handle. The groove receives a pin which rides in the groove. This mechanism causes the toothbrush head to partially rotate or oscillate as the handle moves left-to-right or vice versa in the user's mouth. That rotation or oscillation causes the cleaning elements to move in a vertical plane perpendicular to movement of the toothbrush handle.
Other mechanisms for movement include an arcuate shaped base for a toothbrush head aligned with the longitudinal axis of the head, wherein a movable arcuate block having cleaning elements is flexibly mounted on the toothbrush head such that the block is free to slide on the head in a manner whereby the cleaning elements may travel in a vertical direction generally transverse to the typical side-to-side motion of the toothbrush; and a pivotal mounting of cleaning elements allowing for the elements to move up and down in concert with a side-to-side stroke along the teeth;
A toothbrush head should provide both proper support for the bristles, and be flexible enough during use to allow the bristles to conform to the shape of a user's mouth or teeth. Additionally, construction techniques should be inexpensive, versatile and consistent.
In an attempt to meet these criteria, a process known as “Anchor Free Tufting” (“AFT”) has been used in the formation of toothbrush heads. In such an AFT process, a head plate for holding toothbrush bristles, and for eventual insertion into a toothbrush body, is typically formed of a rigid plastic that is conducive to sonic welding. The head plate is formed with a solid perimeter and defines a field of variously shaped and sized holes within this perimeter. Fibers that are to form the tufts are then placed in the holes in the field of the head plate, and the backs of the tufts are melted together to fix their position relative to one another.
The tufted head plate is then inserted into a predefined receiving portion of the head portion of a toothbrush handle and is sonically welded into place. The brush is then end-rounded and packaged for sale as a traditional toothbrush.
However, this manufacturing process results in a toothbrush with a very rigid head that does not easily conform to the physical characteristics of a user when brushing. Therefore, it would be desirable to provide a toothbrush that can be conveniently manufactured by the above process, but provides the desired flexibility of the head of the toothbrush during use.
It would also be desirable if a toothbrush could be provided having various cleaning/treating elements on a head, such as bristles with different degrees of flexible mounting, to have a enhanced cleaning effect when moved by a mechanical vibratory element.
Further, there is a continuing need in the art for new combinations and arrangements of bristle tufts to provide improved stiffness to enhanced plaque and debris removal, especially within interproximal spaces.